Method for treating gasoline



AUg- 3, 1943 Y .1. J. ALLlNsoN TAL l 2,325,581

METHOD FOR :IREATING GASOLINE Filed April 4, `1940 2 SheetS-Sheet l FIG. I..

AFTEFPA CT/O/VATOR K550/L ER T0 STACK 2 Sheets-Sheet 2 Filed April 4, 1940 @Mon/65,@

PRESSURE w/ w d, 2. L|

M m MN mw mm MM /o 7 w m c f/ 9 ,w m l cV E V m M R 2 .Mw m 0. A l 7 W W y ,L 7

d M m 6 w m L E w \\H /0 Zul' xl!) mmm P m mmm R P mw SQ www f 7 w M ,//W m H 5 .L .A f 5 n 4 5 F 3 5 I Vterialsinost prone to contaminate a vaporphase clay bed and render said bed incapable of reducing the gum content of gasoline tocommercial limits are substantially removed; said preliminary treatment, on the other hand,` usually being insuffl-v cient to reduce the material treated to commercial specications. Y

` More commonly than otherwise airaction No. Y

gasoline produced at unusually high temperatures can ber profitably processedas a single Yfraction throughout, the entire gasoline cut rebenet vfrom, this invention, it is necessary to Y vj.include more andmore material in fraction No. 2

asthe temperature employedV forcracking inl will comprise essentiallyall of those constituents boiling up to about '200 F., and a fraction No. 2 will comprise essentially all of those substances, capable of being incorporated in gasoline,

which boil from 200 F. up; the highest boiling constituents of a No. 2 fraction fwill,at normal :our y present inventionV differs from that disclosed in our previous `application principally in thelnature of.thepreliminaryjtreatment oi fraction No. 1n that application,bothpreliminary Vvand ,nal treatments weregiven'V in the vapor ph`ase. in our'presentfinventionthelpreliminary treatment isV given inutheiiquid phase, and at temperatures whichjarelusually"r morefelevated thanrthose employed',previously:r Fraction No.' 2

' is heated'to temperatures,betweenfapproximately form' of thejpresentvinvention no catalytic material such'as clayfisemployed, and Vthertemperature'lto `which the fraction is elevatedshouldyin general..v exceed 550 F. In order to maintain this: material. in the liquid state,pre'ssures1in eX-, cess of `the vapor' pressureof fraction No. 2 lmust,

be' employed 'solthat the greater concentration vof polymerizable materials,v which will exist ina l 1 liquid Yphaseoi/'er thatpossiblrein arnoregjdispersedvgaseous or vapor phase, will tend to facilithereof, one 'advantage of our invention willimmediat'ely` become Iseli-'evident lto those skilled inthe art. .Sinceonly, the highery boiling portion .ci the il rawcracked gasolinefis subjected to this` type of treatment;'thepressures necessary for maintenance ofjV liquid" phaseV conditions will be Vconsiderably'lessthan would be Athecase if the entire 'gasoline cut were thus treated., .In those 'processes known `to the art in "which polymerizait willfbe obvious to vone skilled inl the art thatV in case an advantage'is foundV to result from changing the temperature which divides fractions Nos. 1: and'2, pressures rmust vbe used in keeping with'` the dividing point temperature .andthe volatility of fraction No. 2.- For reasons hereinafter more fully di-sclo'sedyessentially all ofthe substances incorporated in-cracked gasoline may be profitably subjected to'fboth theprel'iminary and nal treatments if the temperature vemployed for cracking is extremely high;

In general, 200--F- appears to be the most suitable dividing YVpointbetween twoV fractions, pro- 1 vided-temperatures inexcess vof, approximately' 925 F.V have not been employedffor theproducdividing point seems` toj'be desirably sh'ighe'r.

ceiving both the liquid phase treatment under pressure disclosed herein and the subsequent vapor phase treatment. To secure the utmost creases. Apparently, if temperatures of approxi-V mately :1000o F. are employed forv cracking a parafnic 36 gravity gas oil, a dividing pointy of not substantially in excess of l50 F. should separate fractions'Nos. 1 and 2. On the other hand, when crackingmorevolatile,materials at,v l000 F. this Furthermore, 4the source of a charging stockappears to have yan inuence onI the best'v temperature'for dividing the fraction. :The exact dividingnpoint which willl beproductive ofthe lowest catalyst` consumption' isf easily determined Yfor learch separate vcharging stock'and condition yby making trial runs atslightly different dividing points.Vr The difference inthe length of two runs yfor example willV givea clear indication ofthe relative advantages VVAothe respective'fdivision v' tate the formation ofpolyrner's. In consequence temperatures and will indicate Whetherzor-no't another run is necessary to determinethe mosty advantageous point for'division.

' AIn that form of the present invention wherein acatalyst'is employed to"acceleratethe production ofi polymerslower temperatures are,k re-V 1 Yquiredthany when a catalyst is not employed.v

Nevertheless. the vhigher the temperature up to approximately 600 F., the more rapid and-'effective will this' pre-treatment begunder ajgivenV set conditions. HoWeve/rgifthe*temperatureof'treatrnent is increased, the'life joflthe catalyst inj'this liduidplfiase treatment decreases.` At Y temperatures in the neighborhood of 45.0 F.V the catalyst, `after once having 'reachedfa certain equilibrium in a relatively short tirnre'ater the liquid phase Vtowerfhas Vbeen chargedwith fresh orused clay, appears to have an almost indefinite'` life*` :This equilibrium catalyticv power is suin- ,cientr to result in a verylsubstantial yreduction in the' gum content of thepmaterial treated, and

l furthermore to removethosey materials which;

v This advantage isdistinct -ior'gasolinesproducedyA VYsustainthe necessaryreactions so,V that poorer if removed-in theinal vapor phasebed,most

drastically shorten 'its life. Y.

'In many cases this equilibrium. power appearsY to be' somewhat higher than*V thek somewhat'y analogous equilibrium power of Ytheprelinlinary vapor phase treating bed,` disclosed' in our pret vio'us` application, `tending to deliver for the nal treatment material which will form less polymer of a nature moreeas'ilyremovable froml the bed.

at ycrackingV temperatures abov'ef925" F. Y If temperatures y-ofvcloseto 600 F. aregemployed for the liquidphase treatment using a catalyst,V

. the materialfrstprcduced thereby` will be radi-Y cally Vlower in gurncontent than will material producednat 450". F However, there eitheris no equilibrium 4`potency to which-the catalyst ,willfaljl, orjrthisfequilibrium potencyjistoo low-to and poorermaterial is delivered for vaporphase tionV of'thecracked gasoline.V` On'the other hand,

from '9259 upward 'we havediscovered vthat the mostdesirableY dividing` temperature between fractionsfNos. 1v and-2 tends to become steadily lower'.` ljIn fact, Vcertain'-vaprorjphase cracked treatment andV results inally in' faster deteriora- AThis' phenomenon is'alsoevident at temperatureszbetween 500 F. and V550," F.,..although the poisoningof the liquid'phase..catalyst takes place much more slowly at these;-reduced tempera'tures..`

through conduitz to'claytower .wher"ein-:they: become commingled with the vapors of fractionY No. l1' and 4pass concomitantlyhtherewith .downwardly through clay bedl, :the treated portions" to issuelthroughline I 'and the polymers thrdugh conduit l I. Fromv Vafter'-fractionator 23- liquid polymersiformed inpressure"tower 2i .Willbe withdrawn Ythrough conduit L 26 L and thereafter disposed of in any appropriate manner. .Y

` kIn the preferred` manner of carrying outthis.

form of' our invention a quantity ofi-pressure tar 'vequalfto2% to 5% Vrbyvvolumev of the material treated isffinjectedth'rough vconduit/21 intothe suction fof 'pump Al'l-.which will act as a mixing device therefor. f This `pressure .tar may. be'that produced Vbythe same cracking procedure produc- Y tive of thev material treated.1By Virtue ofthe Ainjection of Ysaid pressure tar, .polymerization ofl gum-forming materials 'beginsas'soon as the material approaches the desired temperaturev by vir.

tue of its passage throughheating coil I8: Anv alternative method of inducing .and assuring polymerizationmay vbe practiced'by passing approximately of'fractionNosZ-after having passed through Ypump l'I-through iconduit 28, regulating` valve4 29 vand heating coil wherein`V the temperature of=said5%becornesf elevatedto a temperature -betweenOOv F; and/ 900 F. From heating coil'30 the material passes Vthro-ugh conduit`3l to point '321Whereit rejoins' the main 'stream of fraction No.2. i

The above description iso'f that'formofour iny j vention in 'which no catalystris used `11o-assistl in the formation of polymers. vInfthat form of our invention wherein clay sused., and.L the action of. f `temperature and pressure Y,is4 assisted' by catalysts,V

the procedure will-be substantially similar tothe foregoing,l except that the pressure tower 2| will tions therein existing will 'form' polymers. l Frequently little or noheatingis required for operation in" this manner.'v In certain high pressure types of cracking,-fraction No. 2 will issue from Y stripper'lll as shown in`Fig.f2 through line I6 andil pump Il -at temperatures between V450V"---ls.and

475 F. In those frequentcasesf'whereinfsuchtemperatures are `suilicient, theinaterial Twill proceedfrom-pump Vl1 through by-p'ass'33 to'line 20L-'thence*through tower 2l, conduitZ; aiter' frractionator l23 andlso' on in1 themanner already described in connection withlFig'rl.

If, Online other hand-slightly ingheftempera-jy tures Yarefdesired'orlifby virtue ofg'the materials to' be treated having been produced by cracking Y methods employing lower pressures, 'fractionNo a 2 issues Yfrom stripper l4l-at Substantially-'lowertemperatures, auxiliary heating equipment'should be employed. The'material to be treated-willv then pass fromipump I1 throughvalve 34,conduit 35, Y heat Aexchanger `365 yvalve'allocatedrv 'in line 20, and .thencenasvalrea'dy hereinbefore de-4 scribed." Heat exchanger 36 may ladvar'itageous-kly! be' of ra IV:floating h ea'd Ltubular type tot which heat is supplied bythecirculationof hotA gas oil,- which in generalisV present in excess quantities attem'peraturesgof 600 YE15-lor*greater Y'at'com--. Amercial crackingunits.- j i s Y phase. rather than together. Y. I

seen.V that the In addition to theivariationsalready disclosed,

Vwe have developed amodiflcation of the inven- Y tion vwhich is particularly `ruseful :in special instances for the handling ofA certain stocks. Cer- -tai'nsulphur-bearing gas oils when cracked lend themselves to polymerization with comparative ease. For example, Vwe have discovered that a No. 2 fraction ofcracked gasoline produced from Schulercrude can `be ysuccessfully polymerizedj in the liquid state. by passage through .clay at lower temperatures than'` is possible with material from other sources. v`When such a fraction No. V2 V is produced'by a fractionatorA operating atV elevated pressure, such as pounds per'square inch,` and 'j in consequence issuestherefrom at temperatures ofV from 450 F. `to 475"Y F., passage' as liquid at this temperature throughfa clay bed will satis- Y.

factorily reduce the gum content to commercial specications with an excellent vclay life'. 'Yields' v of* 8,000'ba1'rel'slper tonof fresh clay have regularly been secured,V4 and in some instances very" much superior yields have been secured.

For the practice of the above modiiication vof our invention,A it is necessary only to remove the materials treated in pressure clay towerZ l, shown on Fig. 2,` immediately after :issuing from said' tower 2l through conduit 38 to. conventional and suitable apparatus for the separation of polymers and nished gasoline (not shown); In practice, conduits 33 and lmay-be joined and the treated materials issuing from the' twol towers subjected to a common after-treatment forthe removal of polymers.V

We havefalso discoveredthat. both? the o.-.2'r vfraction vof cracked gasoline produced' 'from' Schulerl crude-and the entiregasoline:'fractionY u comprising 'both fractions Nos.. l and 2 from Schuler crude may be successivelyitreatedateven lower temperatures than 450"eF.A` in theliquid Inv plants Where thercracking procedureis carried Yout atlowerpressure's, in cen-f sequence of which thefgasoline v'fractions would' issue from a fractionator'attemperatureslower: thanY 450 F.,the value of this variationisre'ad-v ilyapparent. vMoreoven; the advantagesfof sepia y arating the cracked-gasolineY intofraction's Nos.: I

phase alone.

1 and 2 is decreasedtfsince the pressure necessary to maintain the. unseparated cracked gasoline wouldbe lower; VSuchfan undivided raw cracked; i gaSOIinacIay-treatedin theli'quidaphase at 350 with the addition of very moder'ate quantities of' anti-oxidant,*produces amotor fuermeetingA Y* commercial gum requirements.

In practicing theaforemenrichedYimwueaudn vof Ythe inventionQtheyalve 40 in-'Fig'. 2 may. be

closedf-and valve: 39 Vopened,g1: assing the more 2 volatile fraction' No. 1 through a condenser, and

then through pipe `Hand pipe 20, to thepressu'reQ clay tower. In this way, both'fractions Nos; 1f

and 2 willrpass through the pressure clay'tower 2|, and then if desiredl through after-fracti'onator 23 and claytower 1.1 'Y

In the foregoing'descriptiongit has been sug-V gestedthat the fraction No.2 should belfed 'into'A clay tower l, together with' fraction No.5 1, when a treatment-:with arelatively active clay catalyst.

is employed. Although this procedure is, under most circumstances,` preferable froml the' view'- point ofl economy, it isof courseclear that sepa-V Y' rate clay towers might be employed, and-the frac-1y tions'Nos. l and 2 separately treated 4in `the vapor In viewiof the above, itwillbe several objects ofthe invention areachieved and other advantageous results attained.,.1; o

`As. manychanges could be madeintheabove -v 6.-."I'he method of treating crackedgasolineconstructions* and methods without departing whichpcomprises separatingjsaid gasolineinto a ".i'rom,V the scope ofthe Vinventiongit isintended" *f* 4vfirst fraction of .relativelyhighvolatility and a i that allymatter `contained in the abovedescip,` @second fraction ofV relatively low volatility, sepa- Y tion or shown inthe accompanying drawings 5 rately treating said second fraction :in liquid shallmbe interpreted as illustrative vand not inra v phase under conditions which promote polymer- Y A i ,j ization of gurnv-forming. constituents, vaporizing limitings'ense. r v y a What is claimed is: f i i the unpolyrnerized portions of said fraction, com-` 1. The method of treating"crackedgasoline i mingling saidvapors with thevapors of` said rst which comprises dividing the` raw cracked gasol0 fraction', and .polymerizing gum-forming` constitline into a rst fraction `ofrelatively high vola-` Vuentslin said combined vapors bypassinglsaidy r n' tility [and ai second fraction of :relatively jlow" vaporsthrougha clay'bed. r i i volatility, `clay-treating `saidsecond fraction inf ,'7. The method 'ofproducing cracked gasoline..`

`; in thevaporphase.

` liquid phase, vaporizling theunpo1ymerizedp0r" Hof low Vgum content `which comprises passing Y tion of said second fractiomcombining the re- 15` the vapors' evolved from petroleum substances `sulting vapors with the vaporsof said'rst fracwhich have been subjected to cracking conditions l .tion,and clay-treatingsaid combined fractions 1 through' a `fractionating -means, therein frac? i tionating said vapors into a highly volatile gaso- 2. The method of jpolymerizingsubst'ances coni linejfraction and into 'a fraction o f comparatively tained in cracked gasoline tojreduce thegum 'con- [20 low volatility containing 4substantially all the ref tent thereof,` which `comprises dividing, said 4,rxiainiriglsubstances suitable for `inclusion in cracked gasolineintoa rst fraction of relatively.` i gasoline and also` into other fractions; removing 1 high volatility anda second fraction Yof' relatively said fraction of `vcomparatively :low volatility,

i forming constituents in v'liquid phase atfaitemflow volatility, treating.saidsecondffraction under passing it in the-"liquidV phase through va bed of Q conditions `promoting polymerization.. of gum- A25-cai;alytic: clay, removing the polymersfirom the unpolymeriz'ed portions of Vsaid fraction, removi perature between 440 F. and 750 F., vaporizing '1 v "ingvsaid highly vola-tile'gasoline fraction from the f the unpolyrrierizedV portion of saidfractioricom- ,i l fractionating means, commingling theevapors J bimng-the'resulting vapors with the fvaplorsof` thereofwi-th the `polymer-freedV vapors of` the first, fraction oflrelativelyhighj volatility` anda i 5 v second `fraction lofi relatively low volatility, :sepa

ratelyA clay-treatngsaid second `iractionjin the H i i f liquid phase at a temperaturenot substantially a `which have been'fs'ubjectedto cracking conditions i iniexcess c1475 F. fand ata pressure"`not sub` Q through a fractionatingmeans;` therein fractionf I `stantially in excessofv500pounds per square inch, fV ating ls'aidjvapors into` a highly volatile gasoline j' i `frernoving the resultingpolymers from" said sec, o jfraction'and into -a fractionoficomparativelylow.i

fsaid first fraction, and passing said COnlbined` B0@fraction:ofcomparatively,low'volatility, simul-i Y vapors through a bed of catalytic clay; V l i j taneously clay-treating the vapors of vboth frac- 3.2The method loi!l Ytreating cracked" gasoline tionsand thereafter separating:polymerizedfromv which comprises separating csaidgasolinelinto `a i llIlpOlyIIleriZed`1'I181.Ii1S-` v i i .ond lfractioniand vaporizing the unpolymerizledf fvolatilityfcontaining substantially all the remain- `infiments,i thereof, combining the,r"esu1tins i vinsfvsubstanes Suitable ,for inclusion inl gasolina y Yvapors with the vapors oi' said rstjfraction and andwalso into other fractions; removing saidfrac- 1 clay-treatinglsaid'combined vapors. Y Y vjtion'of, comparatively low volatility, passing lit in..`

k w14; The methodgot: treatinglcracked gasolinev 5i the liquidphasethroughl a bed `of `catalytic: clay VVwhichcomprises:division,thereof into a fraction i A Y No.1, comprising relatively low-boiling `constittreating,l removing "the polymers from theunpuents and -afraction No; 23comprisingrelativelyfi.v polymerizedportions of said fraction, removing y,

high-boilingconstituents,` clay-'treating'fractionV said highly volatile gasolinefraction from the l tween 350 F. and 600 F., thereafter evaporating l' No. 2 in the liquidrphase at a temperature 'be-` o fractionatingA means,V commingling i the vapors 1' `thereoi'fwith 'the polymer-freedvapors `of the 1Q lthe unpolymerized constituentsoi` fractionNo.`2\,` I" lkfraction rof` `comparatively lovv` volatility, simulcombining the resulting vapors'with "the vapors `taneously clay-treating the vapors of jboth frac-` resulting IJQlymers` from the lunpolyrnerized V por-f 1,

`tions ot the combined fractionslf j o l y pressureV not substantially in excess vof 500 pofundsv Vstantially in excess of"4'75F. throii'gh abed oi:` 4relativr-:ly spent catalytic claypjseparatng Iandl i 1of!raction.No. 1 and simultaneously clay-treating V tions` ands thereaften separating P015liezfd,` f

iromjunpolymerized materials: V fA 9. Iheimethodfloftreatingcracked gasoline,l a fwhich comprises dividing the raw cracked gasoy,5. The method` of treating cracked gasoline' linevint'otwo fractions ofhilgh and low volatility,

the vapors of both fractions, 'andseparating ,ther 5 "which comprises separating saidcracked 'gasoline'4 `5,.separatingandimaintaining ltheinaction of low into a flrst fraction` of relatively high volatility-o amiga second -fraction of relatively low volatility, i passing said secondfraction in liquid phase ata ofY theg gum'forming 'constituents contained per square inch andrat a1 temperature not` sub- 65 of said l fraction .of lowvolatility Sandv mixing the vaporizing fthe lunpolymerizedportions' of` saidv fractionsin the vapor phaser;A 1 1 vsecond fraction and comminglingsaid 'vapors .a

l mingleduvaporslsubstantiallyfreelfrompolymers u l.

withV said "rst fraction, and passingvg'sa'id bmi-- j f: FRANCIS a;

through a second bed of catalytic clay, andthereA afterseparating polymers fromv the gasoline, Y i l The ymethodoffproducing cracked gasoline i 35 ofjlowligurn contentlwhich conlprisesrpassing` the` vapors' evolvedjirom'l petroleum substances A previously employed as a catalyst forvapor phase volatility inliquidphase underconditions which n' Willinduce'polymerization of vat least a portion` tli`erein,fseparating `and removing the resulting x polymers, vaporizing the` nnpolymeriizedportionsv i vapors thereof,` with lthe vapors-of 1said fraction o f T Y removing f therefro'n'i` the. resulting polymers,y jrg-high volati1ityrand'kilay-treating the combined i, 

